scholarly journals Soil particle and moisture-related factors determine landward distribution of bacterial communities in a lateral riverside continuum of the Xilin River Basin

2021 ◽  
Author(s):  
Jingli Yu ◽  
Jingjing Xia ◽  
Qiaoli Ma ◽  
Chi Zhang ◽  
Ji Zhao ◽  
...  
Keyword(s):  
River Basin ◽  
Bacterial Communities ◽  
Soil Particle ◽  
Related Factors

scholarly journals Seasonal Dynamics Are the Major Driver of Microbial Diversity and Composition in Intensive Freshwater Aquaculture

2021 ◽  
Vol 12 ◽  
Author(s):  
Sophi Marmen ◽  
Eduard Fadeev ◽  
Ashraf Al Ashhab ◽  
Ayana Benet-Perelberg ◽  
Alon Naor ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Explanatory Power ◽  
Water Reservoir ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Nutrient Ratios ◽  
Seasonal Cycles ◽  
Fish Feed ◽  
Related Factors ◽  
Freshwater Aquaculture

Aquaculture facilities such as fishponds are one of the most anthropogenically impacted freshwater ecosystems. The high fish biomass reared in aquaculture is associated with an intensive input into the water of fish-feed and fish excrements. This nutrients load may affect the microbial community in the water, which in turn can impact the fish health. To determine to what extent aquaculture practices and natural seasonal cycles affect the microbial populations, we characterized the microbiome of an inter-connected aquaculture system at monthly resolution, over 3 years. The system comprised two fishponds, where fish are grown, and an operational water reservoir in which fish are not actively stocked. Clear natural seasonal cycles of temperature and inorganic nutrients concentration, as well as recurring cyanobacterial blooms during summer, were observed in both the fishponds and the reservoir. The structure of the aquatic bacterial communities in the system, characterized using 16S rRNA sequencing, was explained primarily by the natural seasonality, whereas aquaculture-related parameters had only a minor explanatory power. However, the cyanobacterial blooms were characterized by different cyanobacterial clades dominating at each fishpond, possibly in response to distinct nitrogen and phosphate ratios. In turn, nutrient ratios may have been affected by the magnitude of fish feed input. Taken together, our results show that, even in strongly anthropogenically impacted aquatic ecosystems, the structure of bacterial communities is mainly driven by the natural seasonality, with more subtle effects of aquaculture-related factors.

scholarly journals Zoning the Rate of Pollution in Domestic River Using Spatial Multi - Criteria Evaluation Model

2020 ◽  
Vol 16 (1) ◽  
pp. 49-62
Author(s):  
Amir Ali Abdollahi ◽  
Hossein Babazadeh ◽  
Bahman Yargholi ◽  
Lobat Taghavi
Keyword(s):  
River Basin ◽  
Evaluation Model ◽  
Related Factors ◽  
Study Region ◽  
Water Index ◽  
Multi Criteria Evaluation ◽  
Network Process ◽  
Study Zone ◽  
Zero Values ◽  
Standard Values

AbstractSurface water, especially rivers, is the most important sources of water supplies for drinking, agricultural and industry use and livelihoods. Controlling the pollution of BalikhlouChai River as one of the most important sources of water supply in Ardabil province in Iran is very significance and vital. In this research, the pollution zoning by using the Spatial Multi-Criteria Evaluation (SMCE) model in BalikhlouChai River was carried out to evaluate the trend of changes in water index and other important parameters by considering the physicochemical, biological, socio-economic and cultural constraints. First of all six stations were selected in the study zone and the sampling was performed over a 12 months period, and then the average of obtained parameters was compared with the standard values of Department of Environment in Iran. The results showed that fecal coliform in most stations and BOD5 in stations 4 and 5, and Nitrate in the stations 4, 5, and 6 were more than standard. Next, the related factors and criteria with the changes in pollution trend in river was identified, weighted and prioritized by the Analytical Network Process (ANP) model. Then the basic maps were prepared and the information layers were incorporated into the SMCE model. Finally, the zoning map of BalikhlouChai River specified in terms of pollution and river health in two contaminated and safe areas in the study basin. According to the results of this study, 3 zones for the safe and 3 zones for the contaminated areas in the study region of river basin were determined which respectively the numerical values of 1, 0.85 and 0.75 for the safe zones and 0.2 and 0.1 and about zero values for the contaminated zones were calculated. The results of quality and quantity zoning indicate that the northeast regions of the study area, including Ardabil City outlet and the Qarasu River basin have gained almost zero value.

After the Boomerang: Environmental Movements and Politics in the La Plata River Basin

2002 ◽  
Vol 2 (4) ◽  
pp. 35-57 ◽  
Author(s):  
Kathryn Hochstetler
Keyword(s):  
River Basin ◽  
Legal Capacity ◽  
Related Factors ◽  
La Plata ◽  
Target State ◽  
Transnational Mobilization ◽  
Environmental Norms ◽  
National Environmental

This article focuses on one common transnational NGO strategy, the boomerang strategy. In this strategy, Southern NGOs seek international allies to help them pressure their states from outside. The article uses a case study of a transnational mobilization against a water superhighway or “Hidrovia” in the La Plata River basin in South America to develop arguments about the long term impacts of throws of the boomerang. I argue that what happens after the boomerang depends on two related factors: the extent to which the target state(s) have accepted the international norms at stake and the presence or absence of a specific set of domestic capacities in the target state(s). Because Brazil has higher levels of national environmental legal capacity and greater acceptance of international environmental norms than its neighbors, environmentalists were able to block the Hidrovia there after the successful collective pressure, while Argentine environmentalists were not.

scholarly journals Assessments of Bacterial Community Shifts in Sediments along the Headwaters of São Francisco River, Brazil

Conservation ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 91-105
Author(s):  
Marcos de Paula ◽  
Thiago Augusto Costa Costa Silva ◽  
Amanda Soriano Araújo ◽  
Gustavo Augusto Lacorte
Keyword(s):  
Bacterial Community ◽  
River Basin ◽  
High Intensity ◽  
Bacterial Communities ◽  
Anthropogenic Activities ◽  
Freshwater Ecosystems ◽  
Community Diversity ◽  
Anthropogenic Activity ◽  
Sao Francisco River ◽  
São Francisco River

Sustainable use of freshwater resources for human civilization needs requires the assessment and monitoring of freshwater health, and bacterial communities from riverbed sediments have been shown to be susceptible to chronic anthropogenic disturbances in freshwater ecosystems. Here, we took advantage of the occurrence of well-recognized adjacent sections from the Upper São Francisco River basin with well-recognized levels of anthropogenic activity intensity to test the applicability of sediment bacterial communities as bioindicators of impacts on freshwater ecosystems. We applied 16S amplicon sequencing to estimate the diversity and composition of bacterial communities from 12 sampling sites across the Upper São Francisco River basin, classified as being of no, low, or high intensity of anthropogenic activities, and used diversity metrics and LEfSe to compare the patterns of community structure. Our results revealed that accessed sediment environments associated with land areas with a high intensity of anthropogenic activities presented the lowest levels of community diversity, and the bacterial community compositions of these environments were significantly different from the other sampled areas. Our findings can be considered a source of evidence for the usefulness of bacterial community-based approaches as a tool for diagnosis and monitoring of ecosystem health in areas of vulnerable freshwater environments, and can even be incorporated into regular water quality programs.

scholarly journals Impact of DNA polymerase choice on assessment of bacterial communities by a Legionella genus-specific next-generation sequencing approach

2018 ◽  
Author(s):  
Rui P. A. Pereira ◽  
Jörg Peplies ◽  
Ingrid Brettar ◽  
Manfred G. Höfle
Keyword(s):  
Dna Polymerase ◽  
Bacterial Communities ◽  
Dna Polymerases ◽  
Diagnostic Tools ◽  
High Fidelity ◽  
Related Factors ◽  
Community Profiling ◽  
Proof Reading ◽  
The One ◽  
The Impact

ABSTRACTThe library preparation step is a major source of bias in NGS-based studies. Several PCR-related factors might negatively influence the application of NGS tools in environmental studies and diagnostics. Among the most understudied factors are DNA polymerases. In our study, we evaluated the effect of DNA polymerase type on the characterisation of bacterial communities, more precisely Legionella, using a genus-specific NGS approach. The assay with proof-reading high fidelity KAPA HiFi showed better amplification yield than the one with widely used non-proofreading HotStarTaq. Legionella community richness metrics were significantly overestimated with HotStarTaq. However, the choice of DNA polymerase did not significantly change the community profiling and composition. These results substantiate the use of proof-reading high fidelity DNA polymerases in NGS assays and highlight the need of considering the impact of different DNA polymerases in comparative studies and future guidelines for NGS-based diagnostic tools.

scholarly journals Seasonal dynamics are the major driver of microbial diversity and composition in intensive freshwater aquaculture

2021 ◽  
Author(s):  
Sophi Marmen ◽  
Eduard Fadeev ◽  
Ashraf Al Ashhab ◽  
Ayana Benet-Perelberg ◽  
Alon Naor ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Explanatory Power ◽  
Water Reservoir ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Nutrient Ratios ◽  
Seasonal Cycles ◽  
Fish Feed ◽  
Related Factors ◽  
Freshwater Aquaculture

Aquaculture facilities such as fishponds are one of the most anthropogenically impacted freshwater ecosystems. The high fish biomass reared in aquaculture is associated with an intensive input into the water of fish-feed and fish excrements. This nutrients load may affect the microbial community in the water, which in turn can impact the fish health. To determine to what extent aquaculture practices and natural seasonal cycles affect the microbial populations, we characterized the microbiome of an inter-connected aquaculture system at monthly resolution, over three years. The system comprised two fishponds, where fish are grown, and a "control" operational water reservoir in which fish are not actively stocked. Clear natural seasonal cycles of temperature and inorganic nutrients concentration, as well as recurring cyanobacterial blooms during summer, were observed in both the fishponds and the reservoir. The structure of the aquatic bacterial communities in the system, characterized using 16S rRNA sequencing, was explained primarily by the natural seasonality, whereas aquaculture-related parameters had only a minor explanatory power. However, the cyanobacterial blooms were characterized by different cyanobacterial clades dominating at each fishpond, possibly in response to distinct nitrogen and phosphate ratios. In turn, nutrient ratios may have been by the magnitude of fish feed input. Taken together, our results show that, even in strongly anthropogenically impacted aquatic ecosystems, the structure of bacterial communities is mainly driven by the natural seasonality, with more subtle effects if aquaculture-related factors.

CURRENT STATUS OF CONCRETE REVETMENT IN THE UPPER RIVER BASIN OF CENTRAL AND NORTHERN KYUSHU, JAPAN, AND RELATED FACTORS

2019 ◽  
Vol 75 (2) ◽  
pp. I_367-I_372
Author(s):  
Hidetaka ICHIYANAGI ◽  
Masato YOSHINO ◽  
Ryo IKEGAMI ◽  
Tomoko MINAGAWA
Keyword(s):  
River Basin ◽  
Current Status ◽  
Related Factors

The economic potential of payments for ecosystem services in water conservation: a case study in the upper reaches of Shiyang River basin, northwest China

2012 ◽  
Vol 17 (4) ◽  
pp. 445-460 ◽  
Author(s):  
Zeng Tang ◽  
Yulan Shi ◽  
Zhibiao Nan ◽  
Zhongmin Xu
Keyword(s):  
Ecosystem Services ◽  
River Basin ◽  
Water Conservation ◽  
Northwest China ◽  
Payments For Ecosystem Services ◽  
Economic Potential ◽  
Related Factors ◽  
Shiyang River Basin ◽  
Local Farmers

AbstractIn this paper, we conduct an investigation to assess the economic potential of payments for ecosystem services to conserve water through the conversion of land under irrigation into rain-fed land in the upper reaches of the Shiyang River basin, located in northwest China. We use an approach developed by Antle and Valdivia (2006, Australian Journal of Agricultural and Resource Economics, 50: 1–15) to estimate the supply of water. The analysis shows that it is theoretically possible to reduce agricultural water consumption and subsequently increase the water supply, which would aid the prevention of environmental degradation in the middle and lower reaches of the Shiyang River basin. In addition to the conservation of water, considerable income would be generated by local farmers, which would help to alleviate poverty. Furthermore, the analysis also suggests that more complete data on ecosystem services rates, transaction costs and other related factors would be of value for achieving a more comprehensive assessment.

Practical Importance of Spatial Resolution and Analytical Sensitivity in AEM X-ray Microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 432-433
Author(s):  
J. Zhang ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Spatial Resolution ◽  
Practical Importance ◽  
Beam Current ◽  
Specimen Thickness ◽  
Analytical Sensitivity ◽  
Related Factors ◽  
X Ray ◽  
Probe Size ◽  
Excitation Volume ◽  
Two Parameters

Analytical sensitivity and spatial resolution are important and closely related factors in x-ray microanalysis using the AEM. Analytical sensitivity is the ability to distinguish, for a given element under given conditions, between two concentrations that are nearly equal. The analytical sensitivity is directly related to the number of x-ray counts collected and, therefore, to the probe current, specimen thickness and counting time. The spatial resolution in AEM analysis is determined by the probe size and beam broadening in the specimen. A finer probe and a thinner specimen give a higher spatial resolution. However, the resulting lower beam current and smaller X-ray excitation volume degrade analytical sensitivity. A compromise must be made between high spatial resolution and an acceptable analytical sensitivity. In this paper, we show the necessity of evaluating these two parameters in order to determine the low temperature Fe-Ni phase diagram.A Phillips EM400T AEM with an EDAX/TN2000 EDS/MCA system and a VG HB501 FEG STEM with a LINK AN10 EDS/MCA system were used.

Sign in / Sign up

Export Citation Format

Share Document